1. Field of the Invention
The invention relates to a device connector producing method, a device connector and a molding structure therefor.
2. Description of the Related Art
Japanese Unexamined Patent Publication No. 08-250193 discloses a connector assembly for supplying power to a device, such as a motor of an automotive vehicle. The device is accommodated in a case and the connector assembly is mounted to penetrate the case in inward and outward directions. More particularly, the connector assembly is used by fitting a connector from a power supply into an outer fitting recess and fitting a connector from the power consuming device, such as a motor, into an inner fitting recess.
The above-described device connector is produced by insert molding to form a housing with intermediate terminals embedded therein. An attempt could be made to produce a device connector with a thick part by only one insert molding. However, a defective product may be possibly produced due to air bubbles formed in the thick part or sinks formed on the outer surface thereof. Thus, an intermediate product typically is produced and includes intermediate terminals penetrating therethrough. The intermediate product then is set in a secondary molding die and insert molding is performed to produce the device connector.
The above-described intermediate product can be produced by insert molding or by forming a primary molded body by ordinary injection molding and then press-fitting the intermediate terminals into the primary molded body. Insert molding requires the intermediate terminals to be mounted manually one by one, and hence becomes time-consuming and costly if the number of intermediate terminals increases. On the other hand, a press fitting machine can be used at a relatively low cost to press fit the intermediate terminals into the primary molded body. Thus, producing an intermediate product by injection molding and terminal press-fitting is preferable.
The above-described method for producing the intermediate product by press-fitting the terminals requires forming pilot holes in the primary molded body and then press fitting the intermediate terminals into the pilot holes.
Some connectors require long intermediate terminals. An excessive force may act directly on these long intermediate terminals due to an injection pressure. Hence, the intermediate terminals may be broken or deformed. Additionally, the entire intermediate product may be displaced when the intermediate product is placed in the secondary molding die for insert molding if the intermediate terminals are press-fit insufficiently into the primary molded body. To prevent this problem, the pilot holes into which specific parts of the intermediate terminals can be press-fit to be held must be formed according to the lengths of the intermediate terminals.
The pilot holes are formed while injection molding the primary molded body by providing a primary molding die with core pins. Diameters of the core pins are smaller than the diameters of the intermediate terminals. Therefore, the core pins may be broken or deformed by injection molding pressure during the formation of the primary molded body. The problematic and costly breakage or deformation of the core pins is more probable as the intermediate terminals become narrower and longer. Thus, potential cost advantages achieved by press-fitting intermediate terminals into a primary molded body can be offset by costs associated with the breakage or deformation of long narrow core pins and costs associated with the above-described problems that occur during secondary molding around an intermediate product that has long narrow intermediate terminals.
The present invention was developed in view of the above situation and an object thereof is to enable a cost reduction and a productivity improvement.